GeneWatch PR: Pre-conception gene tests can be dangerous and misleading

GeneWatch UK today responded to reports that the Human Genetics Commission (HGC) will recommend an expansion in gene testing, to include testing children and young people before they have babies. The government advisory body will reportedly tell Government this week that children should be encouraged to take such tests before starting a relationship (1).

"Gene tests can be helpful for some people who know they have a rare disorder in their family", said Dr Helen Wallace, Director of GeneWatch UK "but the idea that young people should be choosing partners or deciding to use IVF based on their DNA is both dangerous and misleading. Most people would be swamped by meaningless information and impossible, confusing choices. Educating children in this way also risks implying that disabled people are not valued members of society".

There are thousands of rare genetic disorders that can be caused either by a single genetic mutation passed from one parent (known as dominant disorders), or by two mutations inherited from both parents (known as recessive disorders). People can be silent carriers of recessive disorders because they do not have the disease themselves and it only appears in their family if they marry another carrier. The HGC appears to be recommending that young people and their partners should consider being tested and not having babies if both parents are a carrier, or if one person has a genetic disorder. This implies also screening any embryos they have through IVF in case they also have the disorder, or a different one. Even if everyone were screened, some children would still have genetic disorders because many mutations occur spontaneously and are not inherited. Because the tests have limited accuracy, some people will also be given wrong assessments of their risk (false positives and false negatives). Conditions such as Downs Syndrome (caused by problems with the mother's egg which become more common with ageing) would not be affected.

There are also rare forms of common diseases which are largely inherited: for example about 5 per cent of cases of breast cancer are thought to be due to rare mutations in one of two genes (the BRCA1 and BRCA2 genes), which increase a women's risk but do not mean she will inevitably get breast cancer. Most diseases are much more complex and involve hundreds or perhaps thousands of genes, each with only a small effect. Smoking, diets and pollution, and social factors such as stress are usually the most important factors in these big killer diseases.

"Giving a spot of blood or spit is simple but the genetic information people get is very complicated" said Dr Wallace, "Even simple tests can sometimes be wrong and complex genetic risk predictions are largely meaningless. People from high risk families need good genetics services but screening large numbers of healthy people for conditions they are never going to get would be a massive waste of precious NHS resources. Teaching more children to eat healthily would be much more beneficial".